U.S. patent number 9,279,462 [Application Number 14/385,782] was granted by the patent office on 2016-03-08 for rotation transmission device.
This patent grant is currently assigned to NTN CORPORATION. The grantee listed for this patent is Koji Akiyoshi, Naotsugu Kitayama, Takahide Saito, Koji Sato. Invention is credited to Koji Akiyoshi, Naotsugu Kitayama, Takahide Saito, Koji Sato.
United States Patent |
9,279,462 |
Kitayama , et al. |
March 8, 2016 |
Rotation transmission device
Abstract
A rotation transmission device includes a control retainer and a
rotary retainer having bars arranged circumferentially alternating
with each other such that pockets are defined between the adjacent
pairs of bars. A pair of rollers are mounted in each pocket with an
elastic member disposed between the pair of rollers such that the
pair of rollers are pushed by the respective bars to their
respective disengaged positions when the control retainer and the
rotary retainer rotate relative to each other. A spring holder is
fitted on an input shaft while abutting one axial end surface of an
inner ring. The spring holder has spring support pieces on the
outer periphery thereof to prevent radially outward movement of the
elastic members. The spring support pieces are plate-shaped members
disposed radially outwardly of the elastic members to extend in the
axial direction in parallel to the outer periphery of the inner
ring.
Inventors: |
Kitayama; Naotsugu (Shizuoka,
JP), Saito; Takahide (Shizuoka, JP),
Akiyoshi; Koji (Shizuoka, JP), Sato; Koji
(Shizuoka, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Kitayama; Naotsugu
Saito; Takahide
Akiyoshi; Koji
Sato; Koji |
Shizuoka
Shizuoka
Shizuoka
Shizuoka |
N/A
N/A
N/A
N/A |
JP
JP
JP
JP |
|
|
Assignee: |
NTN CORPORATION (Osaka,
JP)
|
Family
ID: |
49259494 |
Appl.
No.: |
14/385,782 |
Filed: |
March 12, 2013 |
PCT
Filed: |
March 12, 2013 |
PCT No.: |
PCT/JP2013/056755 |
371(c)(1),(2),(4) Date: |
September 17, 2014 |
PCT
Pub. No.: |
WO2013/146226 |
PCT
Pub. Date: |
October 03, 2013 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20150075935 A1 |
Mar 19, 2015 |
|
Foreign Application Priority Data
|
|
|
|
|
Mar 26, 2012 [JP] |
|
|
2012-069032 |
Mar 29, 2012 [JP] |
|
|
2012-076345 |
Jun 13, 2012 [JP] |
|
|
2012-133730 |
Jun 28, 2012 [JP] |
|
|
2012-145207 |
Jul 25, 2012 [JP] |
|
|
2012-164573 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16D
47/04 (20130101); F16D 41/086 (20130101); F16D
27/118 (20130101); F16D 41/105 (20130101); F16D
41/088 (20130101); F16D 2027/001 (20130101); F16D
2023/123 (20130101); F16D 27/112 (20130101) |
Current International
Class: |
F16D
47/04 (20060101); F16D 27/118 (20060101); F16D
41/08 (20060101); F16D 27/112 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
2005-140145 |
|
Jun 2005 |
|
JP |
|
2005-155834 |
|
Jun 2005 |
|
JP |
|
2006-052838 |
|
Feb 2006 |
|
JP |
|
2009-144771 |
|
Jul 2009 |
|
JP |
|
2009-287724 |
|
Dec 2009 |
|
JP |
|
2009-293759 |
|
Dec 2009 |
|
JP |
|
Other References
International Search Report issued Apr. 23, 2013 in International
(PCT) Application No. PCT/JP2013/056755. cited by applicant .
Japanese Office Action issued Oct. 27, 2015 in Japanese Application
No. 2012-069032 (with partial English translation). cited by
applicant.
|
Primary Examiner: Hansen; Colby M
Attorney, Agent or Firm: Wenderoth, Lind & Ponack,
L.L.P.
Claims
What is claimed is:
1. A rotation transmission device comprising an input shaft having
an end portion, an output shaft having an end portion and arranged
coaxial with the input shaft, a housing covering the end portions
of the input shaft and the output shaft, a two-way clutch mounted
in the housing and configured to selectively transmit torque from
the input shaft to the output shaft, and an electromagnetic clutch
configured to selectively engage and disengage the two-way clutch,
wherein the two-way clutch comprises: an outer ring provided at the
end portion of the output shaft and having an inner periphery and
an opening; an inner ring provided at the end portion of the input
shaft and having an outer periphery; a control retainer including a
plurality of circumferentially spaced apart first bars; a rotary
retainer including a plurality of circumferentially spaced apart
second bars, wherein the first and second bars are disposed between
the inner periphery of the outer ring and the outer periphery of
the inner ring, with the first bars disposed between respective
circumferentially adjacent pairs of second bars, thereby defining
pockets between the respective first bars and the second bars
circumferentially adjacent to the respective first bars; a
plurality of opposed pairs of engaging elements, each opposed pair
of the engaging elements being mounted in one of the pockets; and
elastic members mounted between the respective opposed pairs of
engaging elements and biasing the opposed pairs of engaging
elements toward positions where the engaging elements engage the
inner periphery of the outer ring and the outer periphery of the
inner ring, wherein the inner ring has a first end surface and a
second end surface, the first end surface of the inner ring is
located closer to the opening of the outer ring than is the second
end surface of the inner ring, and the rotation transmission device
further comprises an annular spring holder kept in abutment with
the first end surface of the inner ring so as to rotate together
with the input shaft, the spring holder including spring support
pieces provided on an outer periphery of the spring holder and
configured to prevent radially outward movement of the respective
elastic members, wherein the electromagnetic clutch comprises an
armature connected to the control retainer and movable in an axial
direction of the input shaft, and an electromagnet including an
electromagnetic coil supported by a yoke, wherein the
electromagnetic clutch is configured to move the control retainer
in the axial direction through the armature when the electromagnet
is energized, thereby rotating the control retainer and the rotary
retainer relative to each other in a direction in which
circumferential widths of the pockets decrease, and disengaging the
engaging elements, and wherein the spring support pieces are
plate-shaped members disposed radially outwardly of the respective
elastic members to extend in the axial direction in parallel to an
outer periphery of the input shaft, wherein gaps are defined
between distal ends of the spring support pieces and the outer
periphery of the input shaft such that the elastic members can be
inserted through the gaps.
2. The rotation transmission device of claim 1, wherein each of the
spring support pieces has an inner surface, circumferential side
surfaces, and tapered surfaces formed along intersections between
the inner surface and the circumferential side surfaces,
respectively.
3. The rotation transmission device of claim 1, wherein the spring
holder is constituted by a pressed spring holder.
4. The rotation transmission device of claim 1, wherein the
engaging elements comprise rollers, and wherein the two-way clutch
further comprises a washer fitted on the input shaft and in
abutment with the second end surface of the inner ring, thereby
preventing movement of the rollers toward the second end surface of
the inner ring.
5. The rotation transmission device of claim 4, wherein the washer
has an outer diameter larger than a diameter of a circle passing
through centers of the elastic members.
6. The rotation transmission device of claim 1, wherein the elastic
members comprise coil springs having elliptical cross-sections.
7. The rotation transmission device of claim 1, wherein the
engaging elements comprise rollers, wherein the two-way clutch
further comprises a rotation angle restricting arrangement disposed
between the input shaft and the control retainer and the rotary
retainer and configured to restrict rotation of the control
retainer and the rotary retainer relative to the input shaft beyond
a neutral position in which the rollers are not in engagement with
the inner ring and the outer ring, in directions in which the
control retainer and the rotary retainer are rotated to the neutral
position, respectively.
8. The rotation transmission device of claim 7, wherein each of the
control retainer and the rotary retainer has a flange, and wherein
the rotation angle restricting arrangement comprises a protrusion
formed on the outer periphery of the input shaft, and cutouts
formed in inner peripheries of the respective flanges of the
control retainer and the rotary retainer, and wherein the
protrusion is fitted in the respective cutouts with circumferential
play left between the protrusion and each of the respective
cutouts.
9. The rotation transmission device of claim 1, wherein the rotary
retainer is constituted by a pressed rotary retainer.
10. The rotation transmission device of claim 9, wherein the rotary
retainer further comprises an annular flange formed by pressing and
having protruding pieces formed on an outer periphery of the flange
of the rotary retainer, the protruding pieces being equal in number
to the second bars, and wherein the second bars are formed by
pressing separately from the flange of the rotary retainer, and
fixedly joined to the protruding pieces.
11. The rotation transmission device of claim 1, wherein the
control retainer includes a retainer body comprising an annular
flange having an outer peripheral portion at which the first bars
are provided, and wherein the control retainer further comprises a
tubular member provided on an outer periphery of the retainer body
and connected to the armature, and wherein the tubular body is
formed by pressing, and is fitted in and fixedly joined to the
tubular member.
12. The rotation transmission device of claim 1, wherein the
electromagnet further comprises a male connector which can be
detachably connected to a female connector provided at an end of a
power cord, and wherein the male connector is formed with a
receptacle into which the female connector can be inserted and
which is located at an open end of the housing.
13. The rotation transmission device of claim 12, wherein the male
connector is formed with an engaging hole in which an engaging
portion provided on the female connector is configured to be
snap-fitted.
14. The rotation transmission device of claim 12, wherein the
electromagnetic coil is covered entirely by a coil cover, and
wherein the male connector is formed by molding simultaneously when
the coil cover is formed by molding.
15. The rotation transmission device of claim 1, wherein the
housing has at one end thereof a bearing tube covering the output
shaft and having an open end, and wherein the rotation transmission
device further comprises: a bearing mounted in the bearing tube and
rotatably supporting the output shaft; a backup plate mounted
between the bearing and the open end of the bearing tube; a second
elastic member mounted between the backup plate and the bearing and
biasing the housing in a first direction and the two-way clutch and
the electromagnetic clutch in a second direction opposite the first
direction, thereby preventing axial movements of the two-way clutch
and the electromagnetic clutch relative to each other and to the
housing, with the second elastic member compressed in the axial
direction and with the electromagnet prevented from being pulled
out of the housing; and a guide ring capable of retaining the
second elastic member coaxial with the housing if the second
elastic member were mounted in the bearing tube in a natural state
in which the second elastic member is not compressed in the axial
direction.
Description
TECHNICAL FIELD
This invention relates to a rotation transmission device which can
selectively transmit rotation of one member to another member.
BACKGROUND ART
One known rotation transmission device which can selectively
transmit rotation of a driving shaft to a driven shaft includes a
two-way clutch and an electromagnetic clutch for selectively
engaging and disengaging the two-way clutch.
The rotation transmission device disclosed in JP Patent Publication
2009-287724A includes an outer ring, an inner ring mounted inside
the outer ring, and a control retainer and a rotary retainer each
having bars mounted between the inner and outer rings such that the
bars of the control retainer are arranged circumferentially
alternating with the bars of the rotary retainer, whereby pockets
are defined between circumferentially adjacent pairs of the bars of
the respective retainers. The rotation transmission device further
includes opposed pairs of rollers, each pair being mounted in one
of the pockets, and elastic members mounted between the respective
opposed pairs of rollers and biasing the respective opposed pairs
of rollers away from each other toward stand-by positions where the
rollers can instantly engage a cylindrical surface formed on the
inner periphery of the outer ring and cam surfaces formed on the
outer periphery of the inner ring, whereby when the inner ring
rotates in either direction, one of each opposed pair of rollers
engages the cylindrical surface and the cam surface, thereby
transmitting rotation of the inner ring to the outer ring.
The rotation transmission device further includes an
electromagnetic clutch mounted on an input shaft, which carries the
inner ring. The electromagnetic clutch is configured to move the
control retainer in the axial direction when the electromagnet of
the electromagnetic clutch is energized. When the control retainer
is moved in the axial direction by the electromagnetic clutch, the
retainers are rotated relative to each other in the direction in
which the circumferential widths of the pockets decrease due to the
action of a torque cam provided between the opposed surfaces of a
flange of the control retainer and a flange of the rotary retainer,
whereby the pairs of rollers are moved by the bars of the
respective retainers to the disengaged position, thus preventing
transmission of rotation from the inner ring to the outer ring.
This rotation transmission device is further configured such that
when the control retainer is moved by the electromagnetic clutch in
the direction in which the flange of the control retainer moves
away from the flange of the rotary retainer, the rotary retainer
and the control retainer are rotated relative to each other under
the biasing of the elastic members mounted between the respective
opposed pairs of rollers, in the direction in which the
circumferential widths of the pockets increase, thus allowing the
rollers to instantly engage the cylindrical surface and the cam
surfaces. Thus, when the rollers engage, the rollers move very
little in the circumferential direction, so that the response of
the clutch is good.
This rotation transmission device includes a spring holder
rotationally fixed to the input shaft and kept in abutment with one
end of the inner ring. The spring holder includes braking pieces
(protruding pieces) on its inner periphery, with each braking piece
having a spring support piece on its outer periphery which prevents
radially outward movement of the corresponding elastic member. This
arrangement stabilizes the positions of the respective rollers
pressed by the elastic members, thus making it possible to reliably
press the rollers toward the engaged positions. This in turn
ensures reliable operation of the two-way clutch.
In the rotation transmission device disclosed in JP Patent
Publication 2009-287724A, each spring support piece is formed with
a through hole extending between both side surfaces thereof, and
the elastic members, which are coil springs, are inserted in the
respective through holes to prevent radial movements of the elastic
members. With this arrangement, since the elastic members have to
be inserted into the through holes in a direction perpendicular to
the length direction of the bars, the bars tend to interfere with
the elastic members when inserting the elastic members into the
through holes. Thus, in order to avoid interference with the bars,
the elastic members have to be inserted into the through holes
while being bent in the length direction of the elastic members. It
is therefore difficult to mount the elastic members in position,
and it has been desired to more easily mount the elastic members in
position.
This spring holder is rotationally fixed in position by the
engagement between an engaging surface formed on the inner
periphery of the spring holder and an engaging surface formed on
the input shaft and opposed to the engaging surface of the spring
holder. Thus, the spring holder keeps the control retainer and the
rotary retainer in their respective neutral positions upon abutment
of the bars of the two retainers against the side edges of the
protruding pieces. However, since the bars of the two retainers
tend to collide hard against the protruding pieces when the former
abut the latter, and since there tends to be a slight time
difference between when the bars of one retainer abut the
protruding pieces and when the bars of the other retainer abut the
protruding pieces, the (flat) engaging surface of the spring holder
and the engaging surface of the input shaft, which are in
engagement with each other to rotationally fix the spring holder,
tend to be deformed or become damaged. Deformation of or damage to
the spring holder could detrimentally influence the operation of
the two-way clutch.
If the flat surface and/or the engaging surface is deformed, the
spring holder may be moved axially due to looseness between the
flat surface and the engaging surface. If the control retainer is
inclined with the spring holder displaced axially, the edge on the
inner periphery of the spring holder could engage the outer
periphery of the input shaft and the spring holder could get locked
to the input shaft. If the electromagnetic clutch is de-energized
in this state, the spring holder interferes with the movement of
the control retainer, making it impossible to move the control
retainer to the predetermined engaged position. This makes it
impossible to timely engage the two-way clutch. Thus, it is desired
to reliably and accurately engage the two-way clutch of this
conventional rotation transmission device.
In the rotation transmission device disclosed in JP Patent
Publication 2009-287724A, while not shown, the two-way clutch and
the electromagnetic clutch are entirely covered by a housing.
Ordinarily in such an arrangement, a lead wire is connected to the
electromagnetic coil of the electromagnet forming the
electromagnetic clutch so as to extend to the outside of the
rotation transmission device, and a male connector is connected to
the distal end of the lead wire to which a female connector
connected to the end of the power cord can be detachably
connected.
In this arrangement, since the lead wire is exposed to the outside,
when the rotation transmission device is mounted on an external
device, the lead wire may get caught on an external part and be
broken. The lead wire thus makes handling of the rotation
transmission device difficult. It is desired to make handling of
this rotation transmission device easier.
SUMMARY OF THE INVENTION
An object of the present invention is, in a rotation transmission
device of the above-described type, in which the two-way clutch is
selectively engaged and disengaged by the electromagnetic clutch,
to make it easier to mount the elastic members for biasing the
respective opposed pairs of rollers away from each other.
In order to achieve this object, the present invention provides a
rotation transmission device comprising an input shaft, an output
shaft arranged coaxial with the input shaft, a housing covering end
portions of the input shaft and the output shaft, a two-way clutch
mounted in the housing and configured to selectively transmit
torque from the input shaft to the output shaft, and an
electromagnetic clutch configured to selectively engage and
disengage the two-way roller clutch, wherein the two-way clutch
comprises an outer ring provided at the end portion of the output
shaft and having an inner periphery, an inner ring provided at the
end portion of the input shaft and having an outer periphery, a
control retainer including a plurality of circumferentially spaced
apart first bars, a rotary retainer including a plurality of
circumferentially spaced apart second bars, wherein the first and
second bars are disposed between the inner periphery of the outer
ring and the outer periphery of the inner ring, with the first bars
disposed between respective circumferentially adjacent pairs of
second bars, thereby defining pockets between the respective first
bars and the second bars circumferentially adjacent to the
respective first bars, a plurality of opposed pairs of engaging
elements, each opposed pair of the engaging elements being mounted
in one of the pockets, and elastic members mounted between the
respective opposed pairs of engaging elements and biasing the
opposed pairs of engaging elements toward positions where the
engaging elements engage the inner periphery of the outer ring and
the outer periphery of the inner ring, wherein the inner ring has a
first end surface and a second end surface, wherein the first end
surface is located closer to an opening of the outer ring than is
the second end surface, wherein the rotation transmission device
further comprises an annular spring holder kept in abutment with
the first end surface of the inner ring so as to rotate together
with the input shaft, the spring holder including spring support
pieces provided on the outer periphery of the spring holder and
configured to prevent radially outward movement of the respective
elastic members, wherein the electromagnetic clutch comprises an
armature connected to the control retainer and movable in an axial
direction of the input shaft, and an electromagnet including an
electromagnetic coil supported by a yoke, wherein the
electromagnetic clutch is configured to move the control retainer
in the axial direction through the armature when the electromagnet
is energized, thereby rotating the control retainer and the rotary
retainer relative to each other in a direction in which
circumferential widths of the pockets decrease, and disengaging the
engaging elements, wherein the spring support pieces are
plate-shaped members disposed radially outwardly of the respective
elastic members to extend in the axial direction in parallel to the
outer periphery of the input shaft, and wherein gaps are defined
between the distal ends of the spring support pieces and the outer
periphery of the input shaft such that the elastic members can be
inserted through the gaps.
Since the spring support pieces of the spring holder are
plate-shaped members disposed radially outwardly of the respective
elastic members to extend in the axial direction in parallel to the
outer periphery of the input shaft, gaps are defined between the
distal ends of the spring support pieces and the outer periphery of
the input shaft, so that the elastic members can be inserted
through these gaps.
In the rotation transmission device according to the present
invention, each of the spring support pieces may have tapered
surfaces formed along intersections between the inner surface and
the respective circumferential side surfaces thereof. This prevents
the elastic members from getting caught on edges of the spring
support pieces when the elastic members are compressed, thus making
smooth compression of the elastic members difficult. The elastic
members can thus be compressed smoothly.
If the spring holder is formed by pressing, such a spring holder
can be manufactured easily and thus at a low cost.
A washer may be fitted on the input shaft so as to abut the other
end surface of the inner ring, to prevent movement of the rollers
toward the other end surface of the inner ring. This in turn
prevents separation of the rollers from the pockets. The washer
preferably has an outer diameter larger than the diameter of the
circle passing through the centers of the elastic members so that
the washer prevents not only separation of the rollers but also
separation of the elastic members.
By using coil springs having elliptical cross-sections as the
elastic members, each roller can be pressed by the elastic member
at two points symmetrical to each other with respect to the
longitudinal center of the roller. This prevents skewing of the
rollers.
Preferably, the two-way clutch further includes a rotation angle
restricting means disposed between the input shaft and the control
retainer and the rotary retainer and configured to restrict
rotation of the control retainer and the rotary retainer relative
to the input shaft beyond a neutral position in which the rollers
are not in engagement with the inner ring and the outer ring, in
directions in which the control retainer and the rotary retainer
are rotated to the neutral position, respectively. The rotation
angle restricting means prevents the impact when the control
retainer and the rotary retainer are brought into the neutral
position from being transmitted to the spring holder, thus
preventing the spring holder from becoming loose and inclining,
thereby interfering with the axial movement of the control
retainer. This in turn makes it possible to engage the two-way
clutch with high accuracy.
The rotation angle restricting means may comprise a protrusion
formed on the outer periphery of the input shaft, and cutouts
formed in inner peripheries of the respective flanges of the
control retainer and the rotary retainer, wherein the protrusion is
fitted in the respective cutouts with circumferential play left
between the protrusion and the respective cutouts. The protrusion
may be a key, which is typically used to rotationally fix a rotary
member.
In the rotation transmission device according to the present
invention, by forming the rotary retainer by pressing, it is
possible to reduce the cost of the rotation transmission
device.
In one arrangement, the rotary retainer comprises a flange formed
by pressing and having protruding pieces formed on the outer
periphery of the flange of the rotary retainer, the protruding
pieces being equal in number to the second bars, and the second
bars are formed by pressing separately from the flange of the
rotary retainer, and fixedly joined to the protruding pieces. Such
a rotary retainer can be manufactured easily.
The second bars may be joined to the flange by welding, diffusion
bonding or adhesive bonding.
In another arrangement, the control retainer includes a retainer
body comprising an annular flange having an outer peripheral
portion at which the first bars are provided, and further comprises
a tubular member provided on the outer periphery of the retainer
body and connected to the armature, the retainer body and the
tubular member are separate members from each other with the
tubular body formed by pressing, and the retainer body is fitted in
and fixedly joined to the tubular member. With this arrangement, it
is possible to further reduce the cost of the rotation transmission
device.
By providing the electromagnet with a male connector which can be
detachably connected to a female connector provided at the end of a
power cord, it is possible to omit a lead wire. By omitting a lead
wire, which could get caught on other parts and thus interfere with
the rotation transmission device when the latter is mounted in
position, handling of the rotation transmission device is easy.
Preferably, the male connector is formed with an engaged portion in
which an engaging portion provided on the female connector is
configured to be snap-fitted. With this arrangement, the female
connector can be reliably connected to the male connector.
By covering electromagnetic coil entirely by a coil cover, and
forming the male connector by molding simultaneously when the coil
cover is formed by molding, the male connector can be formed
easily.
In a preferred embodiment, the housing has at one end thereof a
bearing tube covering the output shaft and having an open end, and
the rotation transmission device further comprises a bearing
mounted in the bearing tube and rotatably supporting the output
shaft, a backup plate mounted between the bearing and the open end
of the bearing tube, an elastic member mounted between the backup
plate and the bearing and biasing the housing and internal
components mounted in the housing in opposite directions to each
other, thereby preventing axial movements of the internal
components relative to each other and to the housing, with the
elastic member compressed in the axial direction and with the
electromagnet prevented from being pulled out of the housing, and a
guide ring capable of retaining the elastic member coaxial with the
housing if the elastic member were mounted in the bearing tube in a
natural state in which the elastic member is not compressed in the
axial direction.
In this arrangement, the elastic member biases the housing and the
internal components mounted in the housing in opposite directions
to each other, thus preventing axial movements of the internal
components relative to each other and relative to the housing. This
eliminates the necessity to mount a shim to prevent axial movements
of the internal components, which makes it easier to assemble the
rotation transmission device and thus reduce its cost.
The guide ring mounted in the bearing tube supports the elastic
member so as to be coaxial with the housing in the natural state of
the elastic member, namely before the elastic member is axially
compressed. The guide ring thus allows the elastic member to be
radially expanded without its axis being displaced from the axis of
the housing when the elastic member is elastically axially
compressed while being radially expanded by moving the housing and
the internal components relative to each other. This makes it
possible to reliably prevent axial movements of the internal
components.
According to the present invention, since the spring support pieces
of the spring holder, which are configured to prevent radially
outward movement of the elastic members, are plate-shaped members
disposed radially outwardly of the respective elastic members to
extend in the axial direction in parallel to the outer periphery of
the input shaft, it is possible to insert the elastic members into
the respective pockets through gaps defined between the distal ends
of the spring support pieces and the outer periphery of the input
shaft. The elastic members can thus be extremely easily mounted in
position.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a vertical sectional view of a rotation transmission
device embodying the present invention.
FIG. 2 is a sectional view taken along line II-II of FIG. 1.
FIG. 3 is an enlarged sectional view of a portion of FIG. 2.
FIG. 4 is a sectional view taken along line IV-IV of FIG. 1.
FIG. 5 is a sectional view taken along line V-V of FIG. 4.
FIG. 6 is a sectional view taken along line VI-VI of FIG. 1.
FIG. 7(a) is a sectional view taken along line VII-VII of FIG. 6;
and
FIG. 7(b) is a similar sectional view showing another operational
state.
FIG. 8 is a perspective view of a spring holder shown in FIG.
4.
FIGS. 9(a) and 9(b) are sectional views showing, in a stepwise
manner, how an elastic member is mounted.
FIG. 10 is a sectional view of a different two-way clutch.
FIG. 11 is a sectional view of a different rotation transmission
device embodying the present invention.
FIG. 12 is a sectional view taken along line XII-XII of FIG.
11.
FIG. 13(a) is an enlarged sectional view of a portion of FIG. 12
where there is a rotation angle restricting mechanism; and FIG.
13(b) is a similar sectional view showing the state in which
retainer members are not restricted.
FIG. 14 is a sectional view of a still different rotation
transmission device embodying the present invention.
FIG. 15 is an exploded perspective view of a control retainer
member shown in FIG. 14.
FIGS. 16(a) and 16(b) show, in a stepwise manner, how a retainer
body of a control retainer member is manufactured.
FIG. 17 is a perspective view of a rotary retainer member shown in
FIG. 14.
FIG. 18 is a partially exploded perspective view of a different
rotary retainer member.
FIG. 19 is a sectional view of yet a different rotation
transmission device embodying the present invention.
FIG. 20 is an enlarged sectional view of an electromagnet shown in
FIG. 19.
FIG. 21 is an exploded perspective view of a connector shown in
FIG. 19.
FIG. 22 is a sectional view of another measure for preventing
separation of a coil cover molding the electromagnet relative to
the housing.
FIG. 23 is a sectional view showing how an elastic member is
mounted in a bearing tube of the housing.
FIG. 24 is a sectional view of a guide ring which is a modification
of a guide ring shown in FIG. 23.
FIG. 25 is a sectional view showing the guide ring which has been
mounted in position in a different manner.
DETAILED DESCRIPTION OF THE INVENTION
Now referring to the drawings, the embodiment of the present
invention is described. FIG. 1 shows a rotation transmission device
embodying the present invention. As shown, this rotation
transmission device includes an input shaft 1, an output shaft 2
arranged coaxial with the input shaft 1, and a housing 3 covering
the opposed end portions of the shafts 1 and 2. The rotation
transmission device further includes a two-way clutch 10 mounted in
the housing 3 and configured to selectively transmit rotation from
the input shaft 1 to the output shaft 2, and an electromagnetic
clutch 50 mounted in the housing 3 and configured to selectively
engage and disengage the two-way clutch 10.
The housing 3 is a cylindrical member having a small-diameter
bearing tube 4 at one end of the housing 3. A bearing 5 is mounted
in the bearing tube 4 and rotatably supports the output shaft
2.
Referring to FIGS. 1 to 3, the two-way clutch 10 includes an outer
ring 11 provided at the end of the output shaft 2 and formed with a
cylindrical surface 12 on the inner periphery of the outer ring 11,
and an inner ring 13 provided at the end of the input shaft 1 and
formed with a plurality of circumferentially arranged cam surfaces
14 on the outer periphery of the inner ring 13. A pair of rollers
15 as engaging elements and an elastic member 20 are disposed
between each cam surface 14 and the cylindrical surface 12. The
two-way clutch 10 further includes a retainer 16 retaining the
rollers 15 such that when the inner ring 13 rotates in one
direction, one of each pair of rollers 15 engages the cylindrical
surface 12 and the cam surface 14, thereby transmitting the
rotation of the inner ring 13 to the outer ring 11, and when the
inner ring 13 rotates in the other direction, the other of each
pair of rollers 15 engages the cylindrical surface 12 and the cam
surface 14, thereby transmitting the rotation of the inner ring 13
to the outer ring 11.
A small-diameter recess 17 is formed in the inner surface of the
closed end of the outer ring 11. The input shaft 1 has its end
rotatably supported by a bearing 18 mounted in the recess 17.
The inner ring 13 is integral with the input shaft 1. The cam
surfaces 14, which are formed on the outer periphery of the inner
ring 13, each include a pair of ramps 14a and 14b which are
inclined in opposite directions to each other, and define
wedge-shaped spaces narrowing toward the circumferential ends
thereof in cooperation with the cylindrical surface 12 of the outer
ring 11. Flat spring support surfaces 19 extend in the tangential
directions of the inner ring 13 between the respective pairs of
ramps 14a and 14b to support the respective elastic members 20.
The elastic members 20 are coil springs. In the embodiment, as
shown in FIG. 5, the elastic members 20 have an elliptical
cross-section. As shown in FIG. 3, the elastic members 20 are
disposed between the respective pairs of rollers 15, thus biasing
the respective pairs of rollers 15 away from each other toward
standby positions where the rollers 15 can instantly engage the
cylindrical surface 12 and the cam surfaces 14.
Referring to FIGS. 1-3 and 6, the retainer 16 comprises a control
retainer member 16A and a rotary retainer member 16B. The control
retainer member 16A includes an annular flange 21, and bars 22
equal in number to the number of the cam surfaces 14 and extending
from the radially outer portion of one side of the annular flange
21 while being circumferentially equidistantly spaced apart from
each other. The annular flange 21 is formed with circular
arc-shaped elongated holes 23 between the respective adjacent pairs
of bars 22. The control retainer member 16A further includes a
tubular portion 24 extending from the radially outer edge of the
annular flange 21 in the opposite direction to the bars 22.
The rotary retainer member 16B includes an annular flange 25, and
bars 26 equal in number to the number of the cam surfaces 14 and
extending from the radially outer edge of the annular flange 25
while being circumferentially equidistantly spaced apart from each
other.
The control retainer member 16A and the rotary retainer member 16B
are assembled together in such a way that the bars 26 of the rotary
retainer member 16B extend through the respective elongated holes
23 of the control retainer member 16A such that the bars 22 and 26
are arranged circumferentially alternating with each other. In this
assembled state, the distal ends of the bars 22 and 26 are disposed
between the outer ring 11 and the inner ring 13, while the flange
21 of the control retainer member 16A and the flange 25 of the
rotary retainer member 16B are disposed between a support ring 28
and a spring holder 33 which are both fitted on the outer periphery
of the input shaft 1.
With the retainer members 16A and 16B mounted in position in this
manner, as shown in FIGS. 2 and 3, pockets 27 are defined between
the respective bars 22 of the control retainer member 16A and the
corresponding bars 26 of the rotary retainer member 16B so as to
radially face the respective cam surfaces 14 of the inner ring 13.
A pair of the rollers 15 and one of the elastic members 20 are
received in each pocket 27 with the rollers facing each other.
As shown in FIG. 1, the flange 21 of the control retainer member
16A and the flange 25 of the rotary retainer member 16B are
supported by a slide guide surface 29 formed on the outer periphery
of the input shaft 1 so as to be slidable along the slide guide
surface 29. A thrust bearing 30 is mounted between the flange 25 of
the rotary retainer member 16B and the support ring 28, which is
fitted on the input shaft 1.
The thrust bearing 30 rotatably supports the rotary retainer member
16B while preventing the rotary retainer member 16B from moving
toward the electromagnetic clutch 50.
As shown in FIGS. 1 and 6, a motion converter mechanism in the form
of a torque cam 40 is provided between the flange 21 of the control
retainer member 16A and the flange 25 of the rotary retainer member
16B to convert the axial movement of the control retainer member
16A to the relative rotary motion between the control retainer
member 16A and the rotary retainer member 16B.
As shown in FIGS. 7(a) and 7(b), the torque cam 40 includes opposed
pairs of cam grooves 41 and 42 formed in the respective opposed
surfaces of the flange 21 of the control retainer member 16A and
the flange 25 of the rotary retainer member 16B. The cam grooves 41
and 42 are each deepest at the circumferential center and its depth
gradually decreases toward the respective circumferential ends. A
ball 43 is mounted between one circumferential end of one of each
opposed pair of cam grooves 41 and 42 and the opposite
circumferential end of the other of the pair of cam grooves 41 and
42.
The cam grooves 41 and 42 shown are circular arc-shaped grooves,
but V-shaped cam grooves may be used instead.
The torque cam 40 is configured such that when the control retainer
member 16A is moved in the axial direction in which the flange 21
of the control retainer member 16A approaches the flange 25 of the
rotary retainer member 16B, the balls 43 of the torque cam 40 roll
toward the deepest points of the respective opposed pairs of cam
grooves 41 and 42 (shown in FIG. 7(a)), thereby rotating the
control retainer member 16A and the rotary retainer member 16B
relative to each other in the direction in which the
circumferential widths of the pockets 27 decrease.
Referring to FIGS. 1, 4 and 5, a cylindrical holder fitting surface
32 is formed at the corner between a first axial end surface of the
inner ring 13 and the slide guide surface 29. The holder fitting
surface 32 has a larger diameter than the slide guide surface 29. A
spring holder 33 is fitted on the holder fitting surface 32 and is
in abutment with the first axial end surface of the inner ring
13.
As shown in FIGS. 4 and 8, the spring holder 33 has a diametrically
opposed pair of engaging surfaces 34 on the inner periphery
thereof. The engaging surfaces 34 are in engagement with respective
flat surface portions 35 of the holder fitting surface 32, thereby
keeping the spring holder 33 rotationally and axially fixed in
position.
The spring holder 33 is formed with positioning pieces 36 on its
outer periphery which protrude into the pockets 27 of the retainer
16. The positioning pieces 36 each have first and second
circumferential side surfaces, and are configured to restrict the
rotation angles of the control retainer member 16A and the rotary
retainer member 16B in the disengaging direction by supporting the
bars 22 of the control retainer member 16A on the respective first
circumferential side surfaces and supporting the bars 26 of the
rotary retainer member 16B on the second circumferential side
surfaces. The positioning pieces 36 also prevent movement of the
rollers 15 toward the first end of the inner ring 13.
As shown in FIG. 5, each positioning piece 36 has a spring support
piece 37 which prevents radially outward movement of the
corresponding elastic member 20. Each of the spring support pieces
37 is an L-shaped plate member including an arc portion 37a
integrally connected to the positioning piece 36, and an axially
extending portion 37b integrally connected to the distal end of the
arc portion 37a to extend parallel to the outer periphery of the
inner ring 13. The axially extending portion 37b is located
radially outwardly of the elastic member 20, preventing radially
outward movement of the elastic member 20. An opening 38 is defined
between the distal end of the axially extending portion 37b and the
outer peripheral surface of the inner ring 13 such that the elastic
member 20 can be inserted through the opening 38.
If sharp edges are defined along the intersections between the
inner peripheral surface and the respective circumferential side
surfaces, of each spring support piece 37, the elastic member 20
may get caught on such edges when the elastic member 20 is
compressed, thus making smooth compression of the elastic member 20
difficult. In order to avoid this problem, as shown in FIG. 8,
tapered surfaces 39 are formed along the intersections between the
inner surface and the respective circumferential side surfaces, of
each spring support piece 37.
The spring holder 33 is formed by pressing a steel plate.
As shown in FIG. 5, a washer 45 is fitted on the input shaft 1 at
its end so as to abut both the second axial end surface of the
inner ring 13 and the bearing 18, which rotationally support the
end of the input shaft 1.
The washer 45 has an outer diameter D.sub.0 larger than the
diameter D.sub.1 of a circle on which the centers of the elastic
members 20 lie. The washer 45 prevents separation of the rollers 15
and the elastic members 20 toward the second end of the inner ring
13.
As shown in FIG. 1, the electromagnetic clutch 50 includes an
armature 51 axially facing the end surface of the tubular portion
24 of the control retainer member 16A, a rotor 52 axially facing
the armature 51, and an electromagnet 53 axially facing the rotor
52.
The armature 51 is fitted on a cylindrical radially outer surface
54 of the support ring 28 and rotatably and slidably supported by
the support ring 28. The armature 51 has a coupling tube 55 at its
outer peripheral portion in which the tubular portion 24 of the
control retainer member 16A is press-fitted such that the control
retainer member 16A and the armature 51 are fixedly coupled
together. Since these two members are fixedly coupled together, the
armature 51 is slidably supported by two axially spaced apart
surfaces, i.e. by the cylindrical radially outer surface 54 of the
support ring 28 and by the slide guide surface 29, which is formed
on the outer periphery of the input shaft 1.
The support ring 28 is axially fixed in position by being brought
into abutment with a shoulder 31 of the input shaft 1 formed at the
second axial end of the slide guide surface 29, and is also
rotationally fixed relative to the input shaft 1.
The rotor 52 is axially positioned by a shim 61 disposed between
the rotor 52 and the support ring 28, and is also rotationally
fixed relative to the input shaft 1.
The electromagnet 53 comprises an electromagnetic coil 53a and a
yoke 53b supporting the electromagnetic coil 53a. The yoke 53b is
fitted in the opening of the housing 3 at the second end of the
housing and prevented from separating from the housing 3 by a snap
ring 6 mounted in the opening of the housing at the second end of
the housing. The yoke 53b is supported by the input shaft 1 through
a bearing 60 fitted on the input shaft 1 so as to be rotatable
relative to the input shaft 1.
Now in operation of the rotation transmission device embodying the
present invention, while the electromagnetic coil 53a of the
electromagnetic clutch 50, shown in FIG. 1, is not energized, the
rollers 15 of the two-way clutch 10 are, as shown in FIG. 3, kept
in engagement with the cylindrical surface 12 of the outer ring 11
and the cam surfaces 14 of the inner ring 13.
Thus, when the input shaft 1 is rotated in one direction in this
state, the rotation of the input shaft 1 is transmitted from the
inner ring 13 to the outer ring 11 through one of each pair of
rollers 15, thus causing the output shaft 2 to be rotated in the
same direction as the input shaft 1. When the input shaft 1 is
rotated in the opposite direction, the rotation of the input shaft
1 is transmitted to the output shaft 2 through the other of each
pair of rollers 15.
With the two-way clutch 10 in engagement as described above, when
the electromagnetic coil 53a of the electromagnetic clutch 50 is
energized, an attraction force is applied to the armature 51, so
that the armature 51 is axially pulled toward and pressed against
the rotor 52.
Since the armature 51 is fixedly coupled to the control retainer
member 16A due to the coupling tube 55 and the tubular portion 24
being press-fitted together, when the armature 51 is moved axially,
the control retainer member 16A is moved in the direction in which
the flange 21 of the control retainer member 16A approaches the
flange 25 of the rotary retainer member 16B.
When the control retainer member 16A and the rotary retainer member
16B move relative to each other in this direction, the balls 43
roll from the position shown in FIG. 7(b) toward the position shown
in FIG. 7(a), where the balls 43 are located at the deepest points
of the respective cam grooves 41 and 42. When the balls 43 roll in
this direction, the control retainer member 16A and the rotary
retainer member 16B are rotated relative to each other in the
direction in which the circumferential widths of the pockets 27
decrease.
When the control retainer member 16A and the rotary retainer member
16B rotate relative to each other in this direction, each opposed
pair of rollers 15, shown in FIG. 3, are pushed by the bar 22 of
the control retainer member 16A and the bar 26 of the rotary
retainer member 16B, respectively, toward each other, until the
rollers 15 move to the neutral position.
After the opposed pairs of rollers 15 have disengaged from the
cylindrical surface 12 and the respective cam surfaces 14, when the
control retainer member 16A and the rotary retainer member 16B are
further rotated relative to each other in the direction in which
the circumferential widths of the pockets 27 decrease, the bars 22
and 26 of the retainer members 16A and 16B abut the side surfaces
of the positioning pieces 36 of the spring holder 33, shown in FIG.
4, so that relative rotation between the control retainer member
16A and the rotary retainer member 16B stops, with the opposed
pairs of rollers 15 disengaged.
In this state, since the rollers 15 are disengaged, when the input
shaft 1 rotates, its rotation is not transmitted to the output
shaft 2, so that the input shaft 1 rotates freely.
With the input shaft 1 rotating alone, when the electromagnetic
coil 53a is de-energized, the attraction force applied to the
armature 51 disappears, so that the armature 51 becomes rotatable.
This causes the control retainer member 16A and the rotary retainer
member 16B to be rotated relative to each other in the direction in
which the circumferential widths of the pockets 27 increase, under
the biasing force of the elastic members 20, until the rollers 15
are moved to a stand-by position where the rollers 15 can instantly
engage the cylindrical surface 12 and the cam surfaces 14. In this
state, torque is transmitted between the inner ring 13 and the
outer ring 11 through one of each opposed pair of rollers 15.
If in this state the input shaft 1 is stopped and then rotated in
the opposite direction, the rotation of the inner ring 13 is
transmitted to the outer ring 11 through the other of each opposed
pair of rollers 15.
When the electromagnetic coil 53a is de-energized, since the
control retainer member 16A and the rotary retainer member 16B are
rotated relative to each other in the direction in which the
circumferential widths of the pockets 27 increase such that the
rollers 15 are moved to the stand-by position, where the opposed
pairs of rollers 15 can instantly wedge into the cylindrical
surface 12 and the respective cam surfaces 14, the rollers 15
scarcely move in the rotational direction when the clutch engages.
Thus, the rotation of the inner ring 13 can be instantly
transmitted to the outer ring 11.
Since the rotation torque of the inner ring 13 is transmitted to
the outer ring 11 through rollers 15 which are equal in number to
the cam surfaces 14, it is possible to transmit large rotation
torque from the inner ring 13 to the outer ring 11.
When the control retainer member 16A and the rotary retainer member
16B rotate relative to each other in the direction in which the
circumferential widths of the pockets 27 increase, the balls 43
roll toward the shallow portions of the respective opposed pairs of
cam grooves 41 and 42 until the balls 43 reach the position shown
in FIG. 7(b).
Since the rotation transmission device is configured such that the
two-way clutch 10 engages when the electromagnetic clutch 50 is
switched off, and the two-way clutch 10 disengages when the
electromagnetic clutch 50 is switched on, this rotation
transmission is especially suitable for applications where it is
necessary to meet fail safe requirements.
In the embodiment, the spring support pieces 37 of the spring
holder 33, which prevent radially outward movement of the elastic
members 20, are plate-shaped members that are located radially
outwardly of the respective elastic members 20, and the openings 38
are defined between the distal ends of the respective spring
support pieces 37 and the outer periphery of the inner ring 13 such
that the elastic members 20 can be inserted through the openings
38. In this arrangement, with each of the elastic members 20
positioned so as to face one of the openings 38 as shown in FIG.
9(a), by pushing the elastic member 20 into the opening 38 while
compressing the elastic member 20, the elastic member 20 can be
fitted in the space between the spring support surface 19 of the
inner ring 13 and the portion of the spring support piece 37 facing
the spring support surface 19.
Since the elastic members 20 are inserted in the same direction as
the length directions of the bars 22 and 26 of the control retainer
members 16A and the rotary retainer members 16B, the bars 22 and 26
never interfere with the elastic members 20 when the latter are
fitted in position. The elastic members 20 can thus be easily
fitted in position.
The rollers 15 may be mounted in the respective pockets 27 before
or after mounting the elastic members 20. After mounting the
elastic members 20 and the rollers 15 in position, or
simultaneously with the mounting of the elastic members 20 and the
rollers 15, the washer 45 is fitted onto the end of the input shaft
1.
FIG. 9(b) shows the washer 45 as mounted in position. In this
state, the washer 45 prevents movements of the elastic members 20
and the rollers 15 toward the second end of the inner ring 13. In
other words, by mounting the washer 45 in position, the input shaft
1, rollers 15, elastic members 20, spring holder 33 and washer 45
form a sub-assembly. By inserting this sub-assembly into the outer
ring 11 through its open end, the two-way clutch 10 is
assembled.
In the embodiment shown in FIG. 1, since the control retainer
member 16A and the rotary retainer member 16B are arranged such
that the bars 22 and 26 thereof are disposed between the outer ring
11 and the inner ring 13, and the flanges 21 and 25 thereof, which
axially face each other, are disposed between the outer ring 11 and
the armature 51, it is possible to use an axially short and thus
lightweight outer ring 11.
The two-way clutch 10 used in the rotation transmission device of
the above embodiment is a roller type clutch configured such that
when the electromagnet 53 is de-energized, the control retainer
member 16A is moved axially, and the control retainer member 16A
and the rotary retainer member 16B are rotated relative to each
other in such a direction that the rollers 15 as the engaging
elements engage the inner periphery of the outer ring 11 and the
outer periphery of the inner ring 13. But the two-way clutch of the
present invention is not limited to this particular clutch.
For example, the two-way clutch may be a sprag type clutch shown in
FIG. 10, which includes a small-diameter retainer C.sub.1, and a
large-diameter retainer C.sub.2 provided around the small-diameter
retainer C.sub.1 and comprising a control retainer member 16A and a
rotary retainer member 16B which are exactly identical to the
retainer members 16A and 16B used in the embodiment of FIGS. 1 and
2. A pair of sprags 46, as engaging elements, and an elastic member
47 are mounted in each of the pockets 27 defined between adjacent
pairs of the bars 22 of the control retainer member 16A and the
bars 26 of the rotary retainer member 16B, with the elastic member
47 disposed between the pair of sprags 46. The sprags 46 have their
inner ends inserted in respective ones of pockets 48 formed in the
small-diameter retainer C.sub.1 so as to be pivotable about the
inner ends.
In the embodiment in which the sprag type two-way clutch 10 is
used, when the electromagnet 53 of the electromagnetic clutch 50 is
de-energized, each pair of sprags 46 are pivoted such that their
outer ends move away from each other under the biasing force of the
elastic member 47, thus engaging the inner cylindrical surface 12
of the outer ring 11 and the outer cylindrical surface 13a of the
inner ring 13. When the electromagnet 53 is energized, the control
retainer member 16A is moved axially and simultaneously, the
control retainer member 16A and the rotary retainer member 16B are
rotated relative to each other in such a direction that the bars 22
and 26 of the respective retainer members push the sprags 46 such
that the outer ends of each pair of sprags 46 move toward each
other, until the sprags 46 disengage from the inner cylindrical
surface 12 of the outer ring 11 and the outer cylindrical surface
13a of the inner ring 13.
In the embodiment of FIG. 4, the control retainer member 16A and
the rotary retainer member 16B are kept in the neutral position,
where the rollers 15 are moved to the disengaged position against
the force of the elastic members, by bringing the bars 22 into
abutment with the first circumferential side surfaces of the
positioning pieces 36, which are formed at the outer peripheral
portion of the spring holder 33, and the bars 26 into abutment with
the second circumferential side surfaces of the positioning pieces
36. Thus, the positioning pieces 36 serve as a rotation angle
restricting means which allows relative rotation of the control
retainer member 16A and the rotary retainer member 16B up to the
neutral position but prevents further relative rotation of the
retainer members 16A and 16B in the same direction from the neutral
position. However, the rotation angle restricting means according
to the present invention is not limited to this particular one.
FIGS. 11 to 13 show a different rotation angle restricting means,
which is shown at 70 in FIGS. 11 to 13. The rotation angle
restricting means 70 includes a protrusion in the form of a key 72
fixedly fitted in an axial groove 71 formed in the outer periphery
of the input shaft 1. The rotation angle restricting means 70
further includes a cutout 73 formed in the inner periphery of the
flange 21 of the control retainer member 16A, and a cutout 74
formed in the inner periphery of the flange 25 of the rotary
retainer member 16B. The key 72 is loosely fitted in both of the
cutouts 73 and 74. The key 72 and the cutouts 73 and 74 are
configured such that the control retainer member 16A is kept in the
neutral position when the key 72 abuts one side wall of the cutout
73, while the rotary retainer member 16B is kept in the neutral
position when the key 72 abuts the side wall of the cutout 74 which
is on the opposite side of the one side wall of the cutout 73. In
FIG. 13(a), both the control retainer member 16A and the rotary
retainer member 16B are in their respective neutral positions.
The rotation angle restricting means 70 is configured such that
when the two-way clutch 10 is engaged, the key 72 on the input
shaft 1 is, as shown in FIG. 13(b), spaced apart from both side
walls of either of the cutout 73 formed in the flange 21 of the
control retainer member 16A, and the cutout 74 formed in the flange
25 of the rotary retainer member 16B.
When the rotation angle restricting means 70 is used, the
positioning pieces 36 of the spring holder 33, shown in FIG. 4, are
replaced with projections narrower in width than the positioning
pieces 36 such that while the control retainer member 16A and the
rotary retainer member 16B are kept in their respective neutral
positions by the rotation angle restricting means 70, the bars 22
and 26 are kept out of contact with both side surfaces of the
respective projections.
By providing the rotation angle restricting means 70, which can
keep the control retainer member 16A and the rotary retainer member
16B in their respective neutral positions, between the input shaft
1 and the retainer members 16A and 16B, impact when the control
retainer member 16A and the rotary retainer member 16B are moved to
and stopped at the respective neutral positions is applied only to
the input shaft 1 and not to the spring holder 33, shown in FIG.
4.
This prevents the spring holder 33 from becoming loose and
interfering with axial movement of the control retainer member 16A.
This in turn prevents untimely engagement of the two-way clutch 10,
allowing accurate operation of the two-way clutch 10.
FIGS. 14 and 17 show a different rotation transmission device
embodying the present invention. The rotation transmission device
of this embodiment differs from the rotation transmission device
shown in FIG. 1 in that the control retainer member 16A and the
rotary retainer member 16B are formed by pressing.
The control retainer member 16A of this embodiment comprises a
retainer body 80 formed by pressing, and a tubular member 83. The
retainer body 80 includes an annular flange 81, and bars 82
extending from the outer peripheral portion of one side of the
annular flange 80 so as to be circumferentially equidistantly
spaced apart from each other. The bars 82 are equal in number to
the number of the cam surfaces 14 formed on the outer periphery of
the inner ring 13.
The tubular member 83 is sized such that the tubular member 83 can
be fitted around the outer peripheries of the bars 82, and is
formed with coupling pieces 84 on the radially inner surface
thereof which are equal in number to the number of the bars 82 and
are arranged at equal intervals.
The retainer body 80 and the tubular member 83 are fitted together
by inserting the end of the retainer body 80 including the flange
81 into the tubular member 83 until the flange 81 abuts the
coupling pieces 84. In this state, the coupling pieces 84 and the
flange 81 are joined together at their portions in abutment with
each other, to form the control retainer member 16A. In the
embodiment, they are joined together by welding, but may be joined
together by diffusion bonding or adhesive bonding.
In forming the retainer body 80 by pressing, a blank 85 shown in
FIG. 16(a) is formed by pressing (punching) a steel plate. As
shown, the blank 85 includes an annular plate portion 81a having a
plurality of bar-forming pieces 82a formed on the outer periphery
of the annular plate portion 81a. The bar-forming pieces 82a of the
blank 85 are bent by pressing by 90.degree. relative to the annular
plate portion 81a at their portions integrally connected to the
annular plate portion 81a. FIG. 16(b) shows the blank 85 after the
bar-forming pieces 82a have been bent in the above manner. After
bending the bar-forming pieces 82a, the bar-forming pieces 82a are
cut along chain lines C in FIG. 16(b) to form the bars 82, which
are each formed with a tapered circumferential side surface.
Alternatively, the bars 82 may be formed separately from the flange
81, and may be joined to the flange 81 by welding, diffusion
bonding or adhesive bonding.
Referring to FIG. 17, the rotary retainer member 16B of this
embodiment includes an annular flange 86, and bars 87 extending
from the outer peripheral portion of the annular flange 86 so as to
be circumferentially equidistantly spaced apart from each other.
The bars 87 are equal in number to the number of the cam surfaces
14. The rotary retainer member 16B is substantially identical in
structure to the retainer body 80 shown in FIG. 15, except the
lengths of the bars and the positions of the tapered surfaces.
The rotary retainer member 16B is formed by pressing in the same
manner as the manner in which the retainer body 80 is formed by
pressing as shown in FIGS. 16(a) and 16(b). Thus, the blank from
which the rotary retainer member 16B is formed is not shown.
In this case too, the bars 87 may be formed separately from the
annular flange 86, which is formed by pressing, and may be joined
to the flange 86 by welding.
Since the retainer body 80 of the control retainer member 16A and
the rotary retainer member 16B are formed by pressing as shown in
FIGS. 15 to 17, the retainer members 16A and 16B of this embodiment
can be manufactured at a lower cost.
FIG. 18 shows a still different rotary retainer member 16B, which
includes an annular flange 90 formed by pressing. A plurality of
protruding pieces 91 are provided on the outer periphery of the
annular flange 90 at equal intervals. Each protruding piece 91 is
formed with a cutout 92. Bars 93 formed by pressing are fitted at
one end in the respective cutouts 92 and joined to the protruding
pieces 91 by diffusion bonding.
Since the rotary retainer member 16B of this embodiment comprises a
flange 90 formed by pressing and having protruding pieces 91 on the
outer periphery, and bars 93 formed by pressing separately from the
flange 90, such a rotary retainer member 16B can be manufactured
easily by fixedly joining the bars 93 to the respective protruding
pieces 91.
FIGS. 19 to 22 show a still different rotation transmission device
embodying the present invention. The rotation transmission device
of this embodiment includes a male connector 100 connected to the
electromagnet 53 and configured to be detachably connected to a
female connector 104 provided at the terminal end of a power cord
103. The male connector 100 has a receptacle, into which the female
connector 104 is detachably inserted, located at the open end of
the housing 3.
As shown in FIGS. 20 and 21, the electromagnetic coil 53a is
entirely covered by a coil cover 56 formed by resin molding. The
male connector 100 is formed simultaneously when forming the coil
cover 56.
The male connector 100 includes a terminal 101 connected to the
terminal ends of the electromagnetic coil 53a, and a connecting
tube 102 covering the terminal 101. The female connector 104, which
is provided at the terminal end of the power cord 103, can be
detachably inserted into the connecting tube 102.
The yoke 53b is formed with an annular groove 57 in the end surface
therefore facing the rotor 52, shown in FIG. 19. A connector
inserting hole 58 is formed in the closed end surface of the
annular groove 57. The coil cover 56 is fitted in the annular
groove 57 with the male connector 100 extending through the
connector inserting hole 58, so as not to be pulled out of the
annular groove 57. In order to prevent the coil cover 56 from being
pulled out of the groove 57, the opening of the groove 57 is
crimped in the embodiment. Numeral 59 in FIG. 20 indicates a
protrusion formed by such crimping.
Instead of crimping, as shown in FIG. 22, the coil cover 56 may be
adhesively bonded to the inner surface of the annular groove 57 to
prevent the coil cover 56 from being pulled out of the groove 57.
Numeral 64 in FIG. 22 indicates the adhesive layer.
The female connector 104 has on its top surface a groove 105
extending from the front to rear end surface of the connector 104.
An engaging claw 106 as an engaging portion is received in the
groove 105, and is integrally connected to the female connector 104
at its trailing end with respect to the direction in which the
female connector 104 is inserted into the connecting tube 102 of
the male connector 100 such that the leading end of the engaging
claw 106 can be flexed about the trailing end. The engaging claw
106 has a hook 107 at the leading end thereof.
The hook 107 is configured to be snap-fitted in an engaging hole
108 formed in the male connector 100 when connecting the female
connector 104 to the male connector 100.
In this embodiment, as shown in FIGS. 20 to 22, simultaneously when
forming the coil cover 56, in which the electromagnetic coil 53a of
the electromagnet 53 is wrapped, the male connector 100 is formed,
to which the female connector 104 provided at the terminal end of
the power cord 103 can be detachably connected, and the male
connector 100 is inserted in the connector inserting hole 58 formed
in the yoke 53b such that the receptacle of the male connector 100,
into which the female connector 104 is detachably inserted, is
located at the open end of the housing 3. With this arrangement, no
lead wire is necessary which extends to the outside of the rotation
transmission device.
If a lead wire has to be used, the lead wire could get caught on
other parts of the rotation transmission device while assembling
the rotation transmission device, thus interfering with the
assembling. Or this could lead to breakage of the lead wire. Since
rotation transmission device of this embodiment needs no lead wire,
it is free of the above-mentioned problems, so that it can be
handled easily.
FIG. 23 shows a further different rotation transmission device
embodying the present invention. In this rotation transmission
device, the bearing 5 mounted in the bearing tube 4 of the housing
3 is a bearing having seals. A backup plate 110 is provided between
this bearing 5 and a seal member 7 sealing the open end of the
bearing tube 4. An elastic member 112 is mounted between the backup
plate 110 and the bearing 5. The rotation transmission device of
this embodiment is otherwise identical in structure to the rotation
transmission device shown in FIG. 1. Thus, the entire view of this
embodiment is omitted.
The backup plate 110 is integrally formed on radially inner surface
of the bearing tube 4. The elastic member 112 mounted between the
backup plate 110 and the bearing 5, which includes seals, is a wave
spring 112 mounted in a compressed state.
By mounting the wave spring 112 in a compressed state between the
sealed bearing 5 and the backup plate 110, the wave spring 112
biases the housing 3 and the internal components mounted in the
housing 3, namely the two-way clutch 10 and the electromagnetic
clutch 50, in opposite directions to each other, thus pressing the
electromagnet 53 of the electromagnetic clutch 50 against the snap
ring 6, which is mounted on the inner periphery of the housing 3 at
the second end of the housing 3 to prevent separation of the
internal components. The wave spring 112 thus prevents axial
movements of the two-way clutch 10 and the electromagnetic clutch
50 relative to each other and relative to the housing 3.
This in turn ensures reliable operation of the two-way clutch 10.
Also, compared to a conventional rotation transmission device in
which a shim is used to prevent axial relative movements of the
internal components, the rotation transmission device of this
embodiment can be assembled easily and is less expensive.
While in FIG. 23, a wave spring is used as the elastic member 112,
a disk spring may be used instead. The elastic member 112 is
mounted in the bearing tube 4 in an uncompressed natural state.
With the elastic member 112 mounted in an uncompressed state, the
housing 3 and the internal components are moved relative to each
other in the direction in which the internal components are pushed
toward the elastic member 112, thereby axially compressing the
elastic member 112. In this state, the snap ring 6 for preventing
separation of the electromagnet is mounted at the opening of the
housing 3 at the second end thereof.
Since the elastic member 112 is compressed in the axial direction,
the elastic member 112 is radially expanded by its own spring
force. If the elastic member 112 is radially expanded such that its
axis is displaced from the axis of the housing 3, uneven loads will
be applied to both the housing and the internal components due to
pressure imbalance, thus making it impossible to sufficiently
reduce axial movements of the internal components relative to each
other and to the housing 3.
Thus, in this embodiment, the backup plate 110 is provided at its
radially inner portion with a guide ring 111 having such an outer
diameter that the elastic member 112 can be fitted thereon while
the elastic member 112 is in an uncompressed natural state. With
the elastic member 112 supported and retained by the guide ring 111
so as to be coaxial with the housing 3, the elastic member 112 is
axially compressed by moving the housing 3 and the internal
components relative to each other. With this arrangement, when the
elastic member 112 is compressed, the elastic member 112 can be
radially expanded by its own elastic force without its axis being
displaced from the axis of the housing 3.
While in FIG. 23, the backup plate 110 is integrally formed on the
radially inner surface of the bearing tube 4, as shown in FIG. 24,
the backup plate 110 may be in the form of a snap ring fitted in a
ring groove 113 formed in the radially inner surface of the bearing
tube 4.
While in FIG. 23, the guide ring 111 is provided at the radially
inner portion of the backup plate 110, as shown in FIG. 24, the
guide ring 115 may be provided at the radially inner portion of a
guide plate 114 fitted in the radially inner surface of the bearing
tube 4 and prevented from separation by the backup plate 110.
In another alternative arrangement of FIG. 25, a guide plate 114
having the guide ring 115 at the radially inner portion thereof is
disposed between the bearing 5 and the elastic member 112. With
this arrangement, since the elastic member 112 is radially expanded
by its own elastic force along the surface of the guide plate 114
when the elastic member 112 is compressed, the guide plate 114
prevents damage to a seal S mounted at an opening of the bearing 5.
The guide plate 114 also prevents the radially outer surface of the
elastic member 112 from getting caught on the radially inner
surface of the outer race 5a when the elastic member 112 is
radially expanded, thereby allowing smooth radial expansion of the
elastic member 112.
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